1. Field of Invention
The present invention relates to a wrench that can be switched between a mode where it can drive a socket in a direction and another mode where it can drive the socket in an opposite direction.
2. Related Prior Art
Taiwanese Patent Publication No. 316514 discloses a wrench including a joint 21 for engagement with a socket, a ring 22 to which the joint 21 is attached, a pawl 23 installed on the joint 21, a ring 24, a rotational disk 25, a bolt 26, a ball 27 and a spring 28. The joint 21 includes a square insert 212 for insertion into a square hole defined in the socket and a spring-biased ball detent installed at the square insert 212 for engagement with the wall of the square hole. However, the spring-biased ball detent is not reliable. The joint 21 includes a ridge 211 formed thereon and a hole 215 defined in the ridge 211. A thread is formed on the wall of the hole 215. The ring 22 includes a plurality of teeth formed on an internal face thereof. The pawl 23 includes a toothed side for engagement with the teeth and a smooth side for contact with the ridge 211. The pawl 23 includes a hole 231 defined in a top face thereof. A heart-shaped ring 24 includes two ends 241 inserted in the hole 231. The rotational disk 25 includes a boss 251 formed on a bottom face thereof and a hole 253 defined therein. The boss 251 is engaged with the ring 24 so that rotation of the rotational disk 25 causes rotation of the pawl 23 through the ring 24. The spring 28 and the ball 27 are received in the hole 215. The bolt 26 is inserted through the hole 253 into the hole 215. A thread formed on the bolt 26 is engaged with the thread formed on the wall of the hole 215, thus completing assembly of the wrench. This wrench is deemed structurally complicated.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in the prior art.